CN107979264B

CN107979264B - Line voltage detection circuit and relevant detection method

Info

Publication number: CN107979264B
Application number: CN201610917895.4A
Authority: CN
Inventors: 苏伟全; 蔡孟仁
Original assignee: Leadtrend Technology Corp
Current assignee: Leadtrend Technology Corp
Priority date: 2016-10-21
Filing date: 2016-10-21
Publication date: 2019-10-11
Anticipated expiration: 2036-10-21
Also published as: CN107979264A

Abstract

Line voltage detection circuit and relevant detection method.The embodiment of the present invention provides a kind of line voltage detection circuit, is suitable for a power-supply controller of electric, and there is a high-voltage end to be connected to the line voltage by a high-tension resistive.The line voltage is associated with an AC-input voltage.The line voltage detection circuit includes a high voltage startup transistor, a switchable current source, a bleeder circuit and a management circuit.The high voltage startup transistor is connected to the high-voltage end.The switchable current source is connected between the high voltage startup transistor and a ground line.The bleeder circuit includes two divider resistances, is connected in series between the high-voltage end and the ground line, it is possible to provide a partial pressure result.According to the partial pressure as a result, the management circuit switch switchable current source flows through the high voltage startup transistor and the high-tension resistive selectively to provide a drift current.

Description

Line voltage detection circuit and relevant detection method

Technical field

The present invention relates to the detection circuits of alternating current, more particularly to the detection electricity of the line voltage generated by AC rectification Road and detection method.

Background technique

For exchange turns the power supply unit of direct current, the voltage value of line voltage is often a critically important information. For example, when power supply unit may need on-Line Voltage too low, stop power supply conversion, to prevent operational mistake, this Referred to as under-voltage protection (brown-out protection).When line voltage is sufficiently high, power supply unit normal operating is allowed for Ground provides power supply conversion, this someone is known as foot and suppresses dynamic (brown-in).Moreover, learn the voltage value of line voltage, it can also be right In the operation of power supply unit, line voltage compensation is provided.

The one AC/DC power power supply unit 100 with flyback (flyback) framework of Fig. 1 citing.Bridge rectifier 12 couples of alternating current V_AC-MAINFull-wave rectification is provided, generates input voltage V in input terminal IN_IN, and alternating current V_AC-MAINOne kind can be considered as AC-input voltage.Power-supply controller of electric (power controller) 18, usually an integrated circuit provide pulse width modulation (pulse-width modulation, PWM) signal S_PWM, power switch 26 is controlled, the electricity flowed through in transformer 16 is also controlled Stream.When power switch 26 opens (ON), 16 energy storage of transformer；When power switch 26 closes (OFF), transformer 16 releases energy, passes through Diode 32 establishes output voltage V in output capacitance 30_OUT, supply electricity to load 19.

Diode 14 provides halfwave rectifier, generates line voltage V_LINE.Power-supply controller of electric 18 has a high-voltage end HV, passes through high pressure Resistance 20 is connected to line voltage V_LINE, wherein high-tension resistive not necessarily element, in another embodiment of the invention, high pressure Resistance 20 can be omitted.Power-supply controller of electric 18 can provide high voltage startup function (high-voltage startup).Work as alternating current V_AC-MAINWhen powering at the beginning, power-supply controller of electric 18 can draw a charging current from high-voltage end HV, pass through operation power end VCC charges to operation power capacitor 28, Lai Jianli operating power voltage V_CC.Once operating power voltage V_CCIt is sufficiently high, it fills Electric current is closed, and power-supply controller of electric 18 can just start to provide pwm signal S_PMW。

Fig. 2A illustrates a kind of power-supply controller of electric 18a, and illustrates a kind of detection line voltage V_LINEMethod.Power-supply controller of electric There is a high voltage startup transistor 46 in 18a, opened in high voltage startup, charging current can be provided, to operation power capacitor 28 Charging.Except power-supply controller of electric 18a, a bleeder circuit 40a is connected between high-voltage end HV and ground line GND.Bleeder circuit 40a includes divider resistance 42a and 44a, and tie point can provide partial pressure result to the test side of power-supply controller of electric 18a SENS makes it learn line voltage V_LINEVoltage value.For system designer, this be it is quite convenient because different Divider resistance 42 is combined with 44, so that it may the trigger point that selected under-voltage protection or foot compacting are moved.But on framework, Fig. 2A is high It is expensive, because more two external divider resistance 42a and 44a, and power-supply controller of electric 18a is also required to more pin conducts Test side SENS.

Another kind detection line voltage V_LINEMethod be that the bleeder circuit 40a in Fig. 2A is built into a power-supply controller of electric In, the power-supply controller of electric 18b that is illustrated such as Fig. 2 B.The power-supply controller of electric in power-supply controller of electric 18a, Fig. 2 B compared to Fig. 2A Bleeder circuit 40b is had in 18b, and does not have test side SENS.Power-supply controller of electric 18b may can produce a relatively inexpensive power supply Power supply unit, still, for example, may but sacrifice adjustment or change of the system designer to the trigger point of under-voltage protection.

Summary of the invention

The embodiment of the present invention provides a kind of detection method of a line voltage, is suitable for a power-supply controller of electric, high with one Pressure side is connected to the line voltage by a high-tension resistive.The line voltage is associated with an AC-input voltage.The power-supply controller of electric It include a high voltage startup transistor.The detection method includes: providing a bleeder circuit, including at least has two partial pressures electric Resistance is connected in series between the high-voltage end and a ground line, which has one first input voltage；It should with bleeder circuit detection First input voltage, and a partial pressure result is provided；And according to the partial pressure as a result, one drift current of switch, flows through the high pressure Start transistor and the high-tension resistive.

The embodiment of the present invention also provides an a kind of line voltage detection circuit, is suitable for a power-supply controller of electric, high with one Pressure side is connected to the line voltage by a high-tension resistive.The line voltage is associated with an AC-input voltage.Line voltage detection Circuit includes a high voltage startup transistor, a switchable current source, a bleeder circuit and a management circuit.The high pressure opens Dynamic transistor is connected to the high-voltage end.The switchable current source is connected between the high voltage startup transistor and a ground line.It should Bleeder circuit includes two divider resistances, is connected in series between the high-voltage end and the ground line, it is possible to provide a partial pressure result.Foundation should Partial pressure is as a result, the management circuit switch switchable current source flows through the high voltage startup selectively to provide a drift current Transistor and the high-tension resistive.

Detailed description of the invention

The one AC/DC power power supply unit with flyback framework of Fig. 1 citing.

Fig. 2A, 2B two kinds of power-supply controller of electric of citing.

Fig. 3 shows the power-supply controller of electric implemented according to the present invention.

Fig. 4 shows the signal waveform of some signals in Fig. 3.

Fig. 5 shows another AC/DC power power supply unit with flyback framework implemented according to the present invention.

[symbol description]

12 bridge rectifiers

14 diodes

16 transformers

18,18a, 18b, 18c power-supply controller of electric

19 loads

20 high-tension resistives

26 power switch

28 power capacitors

30 output capacitances

32 diodes

40a, 40b, 40c bleeder circuit

42a, 42b, 42c, 44a, 44b, 44c divider resistance

46 high voltage startup transistors

100,600 AC/DC power power supply unit

202 diodes

204 management circuits

206 switchable current sources

208 under-voltage protecting circuits

209 remove the circuit that quivers

210 foot pressure braking circuits

211 NOT gates

212 signal generators

213 set-reset flip-floops

220 comparators

222 pulse generators

224 control circuits

230 remove the circuit that quivers

232 and door

234 NOT gates

240 d type flip flops

242 and door

CLK clock signal

GND ground line

HV high-voltage end

IN input terminal

I_OSDrift current

IOS fixed value

RG preset range

S_BIConfirmation signal

S_CHKComparison result

The test side SENS

S_PWMPwm signal

S_RESPulse

T1, t2, t3 time point

T_DEB1、T_DEB2Go the time of quivering

V_AC-MAINAlternating current

V_BNODivide result

V_BTMLower voltage limit

V_CCSupply voltage

VCC operation power end

V_HVInput voltage

V_INInput voltage

V_LINELine voltage

V_OUTOutput voltage

V_REFReference voltage

V_TOPUpper limit voltage

Specific embodiment

In the present specification, have some identical symbols, expression have the function of identical or similar structure, principle Element, and for those skilled in the art can according to this specification introduction and deduce.Consider for the succinct degree of specification, phase The element of same symbol will be repeated no longer.

Fig. 3 shows the power-supply controller of electric 18c and some peripheral circuits implemented according to the present invention.In an embodiment In, power-supply controller of electric 18c is an integrated circuit, may replace the power-supply controller of electric 18 in Fig. 1, it is possible to provide pwm signal S_PMWControl function Rate switch 26.

There is a high voltage startup transistor 46 in power-supply controller of electric 18c, is connected to high-voltage end HV.It for example, is a consumption Formula (depletion mode) metal-oxide semiconductor (MOS) (metal-oxide-semiconductor, MOS) transistor to the greatest extent.? It is opened when high voltage startup, charging current can be provided, by diode 202, charged to operation power capacitor 28.Work as operation power Voltage V_CCIt is high to a certain extent when, be for example more than 20V, high voltage startup transistor 46 can because its source voltage is raised and oneself It is dynamic to close, stop providing charging current.As shown in Fig. 3 citing, high voltage startup transistor 46 can by high-voltage end HV and High-tension resistive 20 is electrically connected to line voltage V_LINE。

Power-supply controller of electric 18c include a switchable current source 206, a bleeder circuit 40c, one management circuit 204, one owe 208, one foot pressure braking circuit 210 of voltage protection circuit and a signal generator 212.

There are two divider resistance 42c and 44c for bleeder circuit 40c tool, are series between high-voltage end HV and ground line GND.Point Tie point between piezoresistance 42c and 44c can provide a partial pressure result V_BNO, management circuit 204 is given, control can open accordingly Close current source 206.Bleeder circuit 40c detects the input voltage V in high-voltage end HV_HV, and generate about proportional partial pressure result V_BNO。

When switchable current source 206 is opened, a drift current I can be provided_OS.Drift current I_OSIt is not about 0 Certain value IOS, from line voltage V_LINEStart, flows through high-tension resistive 20, high voltage startup transistor 46 and switchable current source 206.When switchable current source 206 is closed, drift current I_OSIt disappears.Switchable current source 206 can be designed in high voltage startup After end or operating power voltage V_CCWhen enough high, just allow to be turned on.

As shown in Figure 3, management circuit 204 includes comparator 220, pulse generator 222 and control circuit 224.Comparator 220 compares partial pressure result V_BNOWith a reference voltage V_REF, to generate a comparison result S_CHK.It will illustrate later, when Comparison result S_CHKWhen 0 transition logically is 1 in logic, pulse generator 222 can provide a pulse S_RES.Pulse S_RESIn the absence of (logical value 0), manage the continuously off switchable current source 206 of circuit 224.As pulse S_RESWhen appearance, pipe Control circuit 224 just allows clock signal clk triggering to open switchable current source 206.

Pulse generator 222 include quiver circuit (debounce circuit) 230, NOT gate (NOT gate) 234, And with door (AND gate) 232.In this embodiment, as long as comparison result S_CHKFor in logic 0 when, confirmation signal S_BIJust It can be 0 in logic.Only as comparison result S_CHKLogically 0, transition to 1 in logic, and stable 1 logically It is default more than one to remove the time T that quivers_DEB1When, confirmation signal S_BILogical value just can from 0 transformation 1.In this embodiment, the time of quivering is gone T_DEB1About 300us.NOT gate 234 and with door 232 together as a logic circuit, according to comparison result S_CHKAnd confirmation Signal S_BI, to generate pulse S_RES。

It manages circuit 224 and receives clock signal clk and pulse S_RES.As pulse S_RES(in logic when not occurring 0), d type flip flop 240 is reset always (reset), maintains its output for 0 in logic, closes switchable current source 206.Work as arteries and veins Rush S_RESOccur, when being 1 in logic, d type flip flop 240 can pass through when next rising edge of clock signal clk occurs With door 242, switchable current source 206 is opened.In this embodiment, the period of clock signal clk is 100us.

Foot pressure braking circuit 210 receives confirmation signal S_BI.As confirmation signal S_BIFor in logic 1 when, set-reset flip-floop 213 It is set (set), enable signal generator 212.So signal generator 212 can provide pwm signal S_PWM, switch power opens 26 are closed, the power supply unit in Fig. 1 is made to start power supply conversion.

Under-voltage protecting circuit 208 receives confirmation signal S_BI.There is under-voltage protecting circuit 208 NOT gate 211 and one to go to quiver Circuit 209.Functionally, remove to quiver circuit 209 as the circuit 230 that goes to quiver, the time T that goes to quiver for the circuit 209 that only goes to quiver_DEB2With going Quiver the time T that goes to quiver of circuit 230_DEB1It is different.In this embodiment, the time T that quivers is removed_DEB2About 180ms.In other words, when Confirmation signal S_BIWhen lasting 180ms does not become 1 in logic, under-voltage protecting circuit 208 will reset (reset) set-reset flip-floop 213, forbidden energy signal generator 212.At this point, signal generator 212 is forbidden providing pwm signal S_PWM, power switch 26 maintains pass Closed state, the power supply unit in Fig. 1 stop power supply conversion.

In this embodiment, the resistance value of high-tension resistive 20 is about tens of kilohms, and divider resistance 42c and 44c Resistance and about tens of megohms.

Fig. 4 shows the signal waveform of some signals in Fig. 3.It from top to bottom, is line voltage V respectively_LINE, partial pressure result V_BNO, clock signal clk, comparison result S_CHK, drift current I_OSAnd confirmation signal S_BI。

In front half section in Fig. 4, line voltage V_LINEGradually rise；In second half section, line voltage V_LINEGradually decline.

Before time point t1, drift current I_OSFor 0A, line voltage V_LINELower than lower voltage limit V_BTM, do not fallen within pre- If range RG, between upper limit voltage V_TOPWith lower voltage limit V_BTMBetween.Divide result V_BNOApproximately equal to K*V_LINE, it is less than ginseng Examine voltage V_REF, a proportionality constant that wherein K is determined by bleeder circuit 40c.Comparison result S_CHKIt is fixed as 0 in logic, really Recognize signal S_BIIt is 0, pulse S_RESMaintain 0.Therefore, the continuously off switchable current source 206 of circuit 224 is managed.

In time point t1, line voltage V_LINEIt is increased beyond lower voltage limit V_BTM, fall into preset range RG.At this point, partial pressure knot Fruit V_BNO(it is equal to K*V_LINE) it is opposite be more than reference voltage V_REF.So comparison result S_CHKTransition is 1 in logic, pulse S_RESThen it is changed into 1 in logic.And circuit 224 is managed when next rising edge of clock signal clk occurs, unlatching can open Current source 206 is closed, so that drift current I_OSOccur, for the fixed value IOS more than 0A.

Drift current I_OSAppearance, will rapidly drag down input voltage V_HVAnd partial pressure result V_BNO.At this point, partial pressure result V_BNOBy approximately equal to K* (V_LINE- IOS*RHV), wherein RHV is the resistance value of high-tension resistive 20.Therefore, result V is divided_BNOVery It is lower than reference voltage V fastly_REF.Comparison result S_CHKTransition is 0 in logic, pulse S_RESTerminate, control circuit 224 is at once Switchable current source 206 is closed, drift current I is closed_OS.It means that drift current I_OSUnlatching, by feedback after, will lead Cause its closing.In other words, drift current I_OSOne very short time only can be opened, as shown in Figure 4.

Drift current I_OSClosing will lead to partial pressure result V_BNORise, so that comparison result S_CHKLogical value by 0 transition It is 1.As previously described, when next rising edge of clock signal clk occurs, drift current I_OSA Duan Fei can be then turned on The often short time.In other words, drift current I_OSPeriodically, it when the rising edge of clock signal clk each time occurs, is opened Open one very short time.

In time point t2, line voltage V_LINEHave been over upper limit voltage V_TOP.As shown by Fig. 4, time point, t1 was arrived In the period of t2, line voltage V_LINEBetween upper limit voltage V_TOPWith lower voltage limit V_BTM, and drift current I_OSAccording to clock signal CLK is periodically turned on and closes.

On-Line Voltage V_LINEUphill process in, since time point t2, line voltage V_LINEHave been over upper limit voltage V_TOP, do not fall within preset range RG.No matter at this point, drift current I_OSWhether it is turned on, divides result V_BNOBoth greater than with reference to electricity Press V_REF, comparison result S_CHKIt is all 1 in logic.Drift current I at this time_OSIt after unlatching, no longer closes, can believe according to clock ahead of time Number CLK completely carries out a responsibility cycle.As comparison result S_CHKMaintaining logical value 1 is more than to remove the time T that quivers_DEB1When (300us), Namely time point t3, the circuit 230 that goes to quiver just allow comparison result S_CHKPass through, becomes confirmation signal S_BI, just 0 logically Become 1.Then just lead to drift current I_OSSteadily it is closed.

As shown in Figure 4.Period between time point t2 to t3, drift current I_OSWith the logic of clock signal clk Value changes and opens and closes.Drift current I is opened in order to save_OSThe energy being lost, the responsibility cycle of clock signal clk (Duty Cycle) can be designed as 10% or smaller.

Confirmation signal S_BILogically 1 will be maintained always.Until dividing result V_BNOFall to reference voltage V_REF, or Line voltage V_LINEFall to lower voltage limit V_BTM, as Fig. 4 time point t4 is occurred, confirmation signal S_BIWith comparison result S_CHK? It is transformed into 0 in logic.

From Fig. 3 with the analysis of Fig. 4 it is found that dividing result V compared with comparator 220_BNOAnd reference voltage V_REF, carry out detection line Voltage V_LINEWhether preset range RG is fallen into.Moreover, if line voltage V_LINEWithout falling into preset range RG, drift current I_OSIt will Persistently it is closed.On-Line Voltage V_LINEWhen falling into preset range RG, drift current I_OSIt also is only periodically of short duration unlatching. This means that most of the time, drift current I_OSAll it is to close, power supply can be saved.

Via explained above it is found that upper limit voltage V_TOPWith lower voltage limit V_BTMCorrespond with following formula (1) and (2).

K*(V_TOP- RHV*IOS)=V_REF.......(1)

K*V_BTM=V_REF.......(2)

Formula (1) clearly shows that, upper limit voltage V_TOPIt is associated with the resistance value RHV of high-tension resistive 20.Drift current I_OSOut Now, the about default fixed value IOS of integrated circuit.Therefore, system designer can use selection high-tension resistive 20 Resistance value RHV, to determine upper limit voltage V_TOP。

Only on-Line Voltage V_LINEIt has steadily been more than upper limit voltage V_TOPWhen, confirmation signal S_BIIt can be just 1 in logic. It is thus identified that signal S_BIIt can be used as the judgement that under-voltage protection or foot compacting are moved.

As Fig. 3 is illustrated, as confirmation signal S_BIFor in logic 1 when, foot press 210 enable signal of braking circuit generate Device 212.So signal generator 212 can provide pwm signal S_PWM, switch power switch 26 makes the power supply unit in Fig. 1 Start power supply conversion.After more than 180ms, confirmation signal S_BIIt always is 0 in logic, when not becoming 1 in logic, Mean line voltage V_LINEPeak value determination be it is too low, so under-voltage protecting circuit 208 reset foot pressure braking circuit 210 in Set-reset flip-floop 213, forbidden energy signal generator 212, power switch 26 maintain in off position, and the power supply unit in Fig. 1 stops Power supply conversion.

In Fig. 3, line voltage V_LINETouching the discrimination standard that under-voltage protection or foot compacting are moved is upper limit voltage V_TOP, The resistance value RHV of selection high-tension resistive 20 be can use to determine.

Fig. 5 shows another AC/DC power power supply unit 600 with flyback framework implemented according to the present invention, Also it can have the function of high voltage startup, and using the power-supply controller of electric 18c of Fig. 3.There is no the diodes 14 in Fig. 1 by Fig. 5, and The line voltage V of Fig. 5_LINEDirectly provided by bridge rectifier 12.

Although the above present invention is illustrated using the AC/DC power power supply unit of flyback framework as embodiment, this Invention is not limited to this.The present invention is readily applicable to boost converter (booster), buck converter (buck Converter) etc..

The above description is only a preferred embodiment of the present invention, all equivalent changes made according to the claims of the present invention with repair Decorations, are all covered by the present invention.

Claims

1. a kind of detection method of line voltage is suitable for power-supply controller of electric, is connected to high-voltage end by high-tension resistive The line voltage, the line voltage are associated with AC-input voltage, which includes high voltage startup transistor, the detection side Method includes:

Bleeder circuit is provided, including at least there are two divider resistances, is connected in series between the high-voltage end and ground line, high-voltage end tool There is the first input voltage；

First input voltage is detected with the bleeder circuit, and partial pressure result is provided；And

According to the partial pressure as a result, one drift current of switch, flows through the high voltage startup transistor and the high-tension resistive；

Wherein, the detection method also includes:

Compare the partial pressure result and reference voltage, to detect whether the line voltage is more than upper limit voltage, wherein the upper limit voltage It is associated with the resistance value of the high-tension resistive.

2. detection method as described in claim 1, also includes:

Compare the partial pressure result and the reference voltage, to detect whether the line voltage is lower than a lower voltage limit.

3. detection method as claimed in claim 2, wherein define a default model between the upper limit voltage and the lower voltage limit It encloses, which also includes:

When the line voltage is without falling into the preset range, the continuously off drift current.

4. detection method as claimed in claim 3, also includes:

When the line voltage falls into the preset range, the drift current is periodically switched.

5. detection method as claimed in claim 4, also includes:

Clock signal is provided；And

When the line voltage falls into the preset range, according to the clock signal, the drift current is periodically turned on.

6. detection method as described in claim 1, also includes:

The high voltage startup transistor is opened, charging current is provided, is charged to operation power.

7. a kind of line voltage detection circuit is suitable for power-supply controller of electric, is connected to this by high-tension resistive with high-voltage end Line voltage, the line voltage are associated with AC-input voltage, include:

High voltage startup transistor is connected to the high-voltage end；

Switchable current source is connected between the high voltage startup transistor and ground line；

Bleeder circuit, including at least has two divider resistances, is connected in series between the high-voltage end and the ground line, it is possible to provide partial pressure knot Fruit；And

It manages circuit and, selectively to provide drift current, flows through this according to the partial pressure as a result, switching the switchable current source High voltage startup transistor and the high-tension resistive；

Wherein, which includes:

Comparator compares the partial pressure result and reference voltage, to generate comparison result；

Pulse generator, according to the comparison result a, it is possible to provide pulse；And

Control circuit can open the switchable current source when the pulse occurs.

8. line voltage detection circuit as claimed in claim 7, wherein the control circuit receives clock signal, and control electricity Road can open the switchable current source when the signal edge of the clock signal occurs.

9. line voltage detection circuit as claimed in claim 7, wherein the pulse generator includes:

Quiver circuit (debounce circuit) is removed, when it is more than to preset to go to quiver the time that the comparison result, which is stablized, this removes the circuit that quivers The comparison result can be allowed to pass through, become confirmation signal；And

Logic circuit, according to the comparison result and the confirmation signal, to generate the pulse.

10. line voltage detection circuit as claimed in claim 9, also includes:

Under-voltage (brown-out) protects circuit, when the confirmation signal is that the first logical value is more than the first preset time, makes the electricity Source controller stops the power supply conversion of power supply unit.

11. line voltage detection circuit as claimed in claim 10, also includes:

Foot pressure (brown-in) braking circuit makes the power supply unit start power supply when the confirmation signal is the second logical value Conversion.